puller: Support discarding unsupported DDL by setting ignore-txn-start-ts in filter.

[asddongmen]

What problem does this PR solve?

Issue Number: close #12286

What is changed and how it works?

1. DDLs can be skipped in the ddlPuller by setting IgnoreTxnStartTs in the filter configuration. It is also helpful when we need to skip DDLs that cannot be handled by TiCDC.

Check List

Tests

• Unit test
• Manual test (add detailed scripts or steps below)

1. create a changefeed.
2. execute follow ddl upstream

create table a (a bigint primary key, b int);
create table b like a;
rename table a to c, b to a, c to b;

3. changefeed meets the following error:

> ./cdc cli changefeed list
[
  {
    "id": "test",
    "namespace": "default",
    "summary": {
      "state": "warning",
      "tso": 460194169340821515,
      "checkpoint": "2025-08-18 15:17:19.441",
      "error": {
        "time": "2025-08-18T15:17:20.493361+08:00",
        "addr": "127.0.0.1:8300",
        "code": "CDC:ErrHandleDDLFailed",
        "message": "[CDC:ErrHandleDDLFailed]handle ddl failed, query: rename table a to c, b to a, c to b, startTs: 460194169353928710. If you want to skip this DDL and continue with replication, you can manually execute this DDL downstream. Afterwards, add `ignore-txn-start-ts=[460194169353928710]` to the changefeed in the filter configuration.: [CDC:ErrSnapshotTableNotFound]table 112 not found in schema snapshot"

4. Adjust changefeed filter config file cf.toml, add the ignore-txn-start-ts=[460194169353928710] to filter.

[filter]
ignore-txn-start-ts = [460194169353928710]

5. Update chagnefeed with cf.toml.

./cdc cli changefeed update -c test --config=cf.toml 

6. resume changefeed, chagnefeed resume to normal.

> ./cdc cli changefeed list
[
  {
    "id": "test",
    "namespace": "default",
    "summary": {
      "state": "normal",
      "tso": 460194185921429508,
      "checkpoint": "2025-08-18 15:18:22.691",
      "error": null
    }
  }
]

Questions

Will it cause performance regression or break compatibility?

Do you need to update user documentation, design documentation or monitoring documentation?

Release note

Support discarding unsupported DDL by setting `ignore-txn-start-ts` in filter.

[gemini-code-assist]

Summary of Changes

Hello @asddongmen, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

The pull request introduces a new filtering mechanism in TiCDC's ddlPuller component. This enhancement allows users to explicitly skip or discard specific DDL (Data Definition Language) operations that might be unsupported or cause issues during replication, by configuring a list of transaction start timestamps (ignore-txn-start-ts). This provides greater control and resilience for changefeeds encountering problematic DDLs.

Highlights

• Configurable DDL Discarding: Implemented a new ignore-txn-start-ts configuration option within the filter, enabling the ddlPuller to skip DDLs based on their transaction start timestamp.
• Enhanced ShouldDiscardDDL Functionality: The ShouldDiscardDDL function now accepts the DDL's transaction start timestamp, allowing for more granular control over which DDLs are discarded.
• Improved DDL Handling Logic: Updated the ddlPuller's internal logic, particularly for complex DDLs like RENAME TABLE, to properly utilize the new ignore-txn-start-ts filter when determining whether to discard a DDL.
• Comprehensive Test Coverage: Added new unit tests to validate the correct behavior of the ddlPuller and the filter, ensuring that DDLs are discarded as expected when ignore-txn-start-ts is configured.

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[gemini-code-assist]

Code Review

This pull request introduces a useful feature to skip problematic DDLs using ignore-txn-start-ts. The changes to the filter interface and its usage across the ddl_puller are mostly correct. I've identified a bug where CREATE TABLES DDLs cannot be skipped by startTs and a leftover debug log message that should be removed. The tests for the new functionality are well-written.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: 3AceShowHand, lidezhu

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [3AceShowHand,lidezhu]

Approvers can indicate their approval by writing /approve in a comment
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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-08-18 07:35:22.566759978 +0000 UTC m=+252530.509935484: ☑️ agreed by lidezhu.
• 2025-08-18 09:07:08.87383628 +0000 UTC m=+258036.817011786: ☑️ agreed by 3AceShowHand.

[asddongmen]

/test pull-dm-integration-test

[asddongmen]

/retest

[asddongmen]

/test pull-cdc-integration-kafka-test

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.5: #12288.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #12289.
But this PR has conflicts, please resolve them!

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #12290.
But this PR has conflicts, please resolve them!

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.1: #12291.
But this PR has conflicts, please resolve them!